I dont know why but i relaunch arduino ide and then the warning was: "library rfid-master claims ti run over(avr,STM32F1, teensy, esp8266) architectures and may be incompatible with you current board wich runs on (pic32) architetures"

When i upload from Arduino IDE, first appears A warning "library MFRC522 claims to run on [avr architectures and my be incompatible with your current board which runs on STM32F1 architectures], and then in serial monitor nothing appears